- Keys can contain any valid JSON values
- scalars, objects or arrays
- Nested or not
- Data is stored decoded in binary format
- JSONPath like syntax for direct access to elements
- Strongly typed atomic commands
Syntax:
JSON.SET <key> <path> <json>
It sets the JSON value at path in key. For new Redis keys the path must be the root. For existing keys, when the entire path exists, the value that it contains is replaced with the json value.
>> JSON.SET scalar . ' "Hello JSON!" '
"OK"
>> JSON.GET scalar
"\"Hello JSON!\""
>> JSON.SET object . '{"foo":"bar", "ans":"4" }'
"OK"
>> JSON.GET object
"{\"foo\":\"bar\",\"ans\":\"4\"}"
>> JSON.GET object .ans
"\"4\""
As shown above, you can retrieve one part of the document by using .ans
Let us look at JSON Object Example. A JSON object contains data in the form of key/value pair. The keys are strings and the values are the JSON types. Keys and values are separated by colon. Each entry (key/value pair) is separated by comma.
The { (curly brace) represents the JSON object.
{
"employee": {
"name": "alpha",
"age": 40,
"married": true
}
}
>> JSON.SET employee_profile . '{ "employee": { "name": "alpha", "age": 40, "married": true } } '
"OK"
JSON.GET <key>
[INDENT indentation-string]
[NEWLINE line-break-string]
[SPACE space-string]
[NOESCAPE]
[path ...]
It return the value at path in JSON serialized form.This command accepts multiple path s, and defaults to the value's root when none are given.
The following subcommands change the reply's format and are all set to the empty string by default: * INDENT sets the indentation string for nested levels * NEWLINE sets the string that's printed at the end of each line * SPACE sets the string that's put between a key and a value
>> >> JSON.GET employee_profile
"{\"employee\":{\"name\":\"alpha\",\"age\":40,\"married\":true}}"
JSON.TYPE [path]
It reports the type of JSON value at path and path defaults to root if not provided. If the key or path do not exist, null is returned.
>> JSON.TYPE employee_profile
"object"
JSON array represents ordered list of values. JSON array can store multiple values. It can store string, number, boolean or object in JSON array.
In JSON array, values must be separated by comma.
The [ (square bracket) represents JSON array.
JSON Array of Objects Let's see a simple JSON array example having 4 objects.
{"employees":[
{"name":"Ram", "email":"[email protected]", "age":23},
{"name":"Shyam", "email":"[email protected]", "age":28},
{"name":"John", "email":"[email protected]", "age":33},
{"name":"Bob", "email":"[email protected]", "age":41}
]}
>> JSON.SET testarray . ' {"employees":[ {"name":"Ram", "email":"[email protected]", "age":23}, {"name":"Shyam", "email":"[email protected]", "age":28}, {"name":"John", "email":"[email protected]", "age":33}, {"name":"Bob", "email":"[email protected]", "age":41} ]} '
"OK"
>> JSON.GET testarray
"{\"employees\":[{\"name\":\"Ram\",\"email\":\"[email protected]\",\"age\":23},{\"name\":\"Shyam\",\"email\":\"[email protected]\",\"age\":28},{\"name\":\"John\",\"email\":\"[email protected]\",\"age\":33},{\"name\":\"Bob\",\"email\":\"[email protected]\",\"age\":41}]}"
A JSON object can have another object also. Let's see a simple example of JSON object having another object.
>> JSON.SET employee_info . ' { "firstName": "Sonoo", "lastName": "Jaiswal", "age": 27, "address" : { "streetAddress": "Plot-6, Mohan Nagar", "city": "Ghaziabad", "state": "UP", "postalCode": "201007" } } '
"OK"
>> JSON.GET employee_info
"{\"firstName\":\"Sonoo\",\"lastName\":\"Jaiswal\",\"age\":27,\"address\":{\"streetAddress\":\"Plot-6, Mohan Nagar\",\"city\":\"Ghaziabad\",\"state\":\"UP\",\"postalCode\":\"201007\"}}"